Oklahoma as metaphor

Ask someone (even some one in this state) about cultural mentions of Oklahoma and if you are lucky enough to get three answers, you may get:

1. Steinbeck's Grapes of Wrath
2. Rogers and Hammerstein's musical Oklahoma!
3. Woody Guthrie's This Land is My Land

But it takes an Estonian to point out that Kafka used Oklahoma as a metaphor for America. And to think that when I went to Estonia, all I did was snark ... (and as the comment on my post implies, I was just being ignorant when I wrote it).